Combined telephone and telautograph exchange system.



P. RITCHIE. COMBINED TELEPHONE AND TELAUTOGRAPH EXCHANGE SYSTEM.

APPLIOATION FILED 0013.12, 1908.

Patented July 26, 1910.

ii: H

FOSTER RITCHIE, or ACTON, ENGLAND.

COMBINED TELEPHONE AND TELAUTOGRAPH EXCHANGE SYSTEM.

Specification of Letters Patent.

To all whom it may concern:

Be it known that I, FOSTER RITCHIE, a subject of'the King of Great Britain, residing, at 36 King Edwards Gardens, Acton, in the county of Middlesex, England, electrical engineer, have invented certain new and useful Improvements in a Combined Telephone and Telautograph Exchange System, of which the following is a specification.

The object of this invention is to provide meansfor subscribers on an exchange sys tem in which both telephones and telautographs are installed being put into communication with each other through the ex change so that they may speak, write or give calls or signals without interfering with the exchange apparatus. i

In the system proposed according to the present invention, storage battery which when the subscribers line is not in usevis being charged from the exchange, the breaking of this circuit by the subscriber causing the calling signal at the exchange to be actuated. Subsequent communication with the exchange is by telephone and means are provided whereby the exchange may ring up any subscriber.

' quired for signaling,

These and other novel features of the system are hereinafter more particularly described with reference to the accompanying'diagrammatic drawings in which Figure 1 shows the various circuits reandFig. 2 a calling indicator at the exchange switch board which is shown as a special form of shutter indicator but maybe of any other suitable form, as for example, small electric lamps controlled by suitable relays.

In Fig. 1 the exchange apparatus generally is denoted by A andthe subscribers by B. At the exchange is a dynamo a or other suitable source of current, the negative terminal 'ofwhich is earthed while the positive terminal is connected with line 1 through wire 2, indicator b and jack 0. The current from the dynamo passes along line 1 to a -subscribers station through upper contact (1' of switch 05, wire 3, master switch spring (2, part of the telautograph receiving apparatus f, battery h, and master switch spring e to earth, thus chargingthe battery h. This current holds up the indicator shutter b but removal of the telephone receiver. from the hook of switch d breaks each subscriber has a I operate the indicator this circuit at contact d and the shutter Patented July 26, 1910. Application filed October '12, 1908. Serial No. 457,411.

falls, thereby giving a calling signal. The

exchange operator then inserts a plug in jack 0 and by means of switch 9 connects the exchange telephone to through contacts g, 9 to lines 1, l and through them and the lower contacts (13, d of switch d to subscribers telephone apparatus '0. Having ascertained the subscriber required the operator plugs in the proper jack and informs the calling subscriber that he is through. Under this condition the charging circuit is broken at the jacks and either the two subscribers telephone apparatus are connected over lines 1, t in which case the working current is supplied by a part it of each but tery connected by wires 10, 11 with the telephone apparatus, orif both submaribers telephones are replaced, the line 4: has in cir cuitat each end the master switch spring (1, push 71, contacts j, bell 7c, battery h, and master sjwitch spring 0 As the two batteries are connected in opposition no current passes along the line, but on. the calling subscriber depressing the push current from the cal led subscribers battery passes through his bell is along line t and thence through master switch spring 6 and lower contact of calling subscribers push i and wire 5 to earth. The two subscribers are thus enabled to correspond either by telephone or telautograph. The ringing circuit is completed by closing the contacts of switch Z at the exchange and thereby connecting the line 4 to earth. The clearing or ring-01f indicator p is connected in series with a condenser across the lines 1, 4 and is operated by induced impulses sent from the subscribers station by operatively connectin a transformer a with line on'the one han and the subscribers battery on the other. This is effected by means of a springreturned push 1, by depressing which momentarily the secondary of the transformer is connected through contact s with line wires 1, i and subsequently the primary of the transformer is connected through contact t with subscribers battery h. This causes an impulse to be sent over the lines which vis generally sufficient to p butvin any case a second impulse is sent over the linesby the contacts it being again closed momentarily on the release of the ush a When sending a written message the master switch springs e, e, e are moved to the left as indicated by the arrow in Fig. 1 so cutting the receiving apparatus indicated at '15 its upper stop when the receiving mechan ism is brought into operation, thereby cuting apparatus f in line.

In telautographs depending upon varying currents for the movements of the pen it is ting out the bell k and inserting the receiv necessary that the resistance of the line circuits should be fairly constant and for this purpose the resistance coils 6, 7 8, 9 are interposed in the cord circuit when a junction swire to another exchange is not required, the combined resistance of 6 and 7 being arranged to be equalto one junction wire, and that of 8 and 9 to the other. The resistance of subscribers lines to their respective exchanges are all brought up to a standard value, so that under normal conditions the line circuits between any pair of subscribers have a definite and constant value. Inthe calling indicator 6 shown in Fig.

2 theshutter is provided with a double catch in order that the exchange operator may be able to restore the indicator when the call has been attended to, before the charging current is again passing through 4 it. As shown in the drawing-the shutter is held upWith the armature in the released position as it would be when the charging current is broken at' the jack. When the plug is withdrawn and the charging current is again established, the armature b is attracted and the shutter after dropping forward very slightly is arrested by the upper catch. On the subscriber making a call and thus again breaking the icharging circuit This movement of the master duce the shutter is released .by the upper catch and falls to the calling position.

Having thus described the nature of my said invention and the best means I know of carrying the same into practical effect, I claim 1. A combined telautograph and telephone exchange system comprising a local battery at each subscribers station, circuit connections placing these local batteries normally in opposition, and means operative when sending a written message whereby the polarity of the battery of the sender is reversed, substantially as described.

2. A combined telautograph and telephone exchange systemcomprising a local battery and a call bell at each subscribers station and means at the calling subscribers station whereby the battery of the called up subscriber is grounded and a circuit established through his bell, substantially as described.

3. Ina combined telautograph and telephone exchange system comprising a local battery at each subscribers station and a ring-off indicator at the exchange, means for o crating the ring-ofl' indicator by ind currents, said means comprising a transformer and means for successively connecting the secondary of the tra nsformer with line and its primary with the subscribers battery, substantially as described. 4. A combined telautograph and telephone exchange system comprising transmitting and receiving apparatus and a local battery at each subscribers station, circuits connecting said apparatus and a switch in the transmitting apparatus of each subscriber adapted to ground the batteries of the other subscribers and complete the calling circuit, substantially, as described.

In testimony whereof I have signed my name to this specification in the presenceof two subscribing witnesses.

JOSEPH MILLARD WALTER J. 

